Well, it could be a sump gasket,or the o-ring around the filler tube if it has one,or a valve cover gasket...if it was a crank seal under the flywheel ,I don't think it would be so easy to see ,until it made it pass the rewind housing ....
Jim

Check where the bracket holds the oil filler tube in place--see if the little screw is still holding the tube in place, or the rubber o-ring on the oil filler tube is leaking! Do not remove the "big nut" on top of the flywheel, nor try to remove the flywheel, unless you know the correct way to do it! Like the other person said--it probably ain't leaking out the top!
Then, turn the mower up with the carb up, and see if oil is leaking out underneath, by the crankshaft. Pull spark plug wire for this procedure!!
Then, clean the engine, and see if oil is leaking out where the top and bottom parts of the engine is bolted to gether.
by: Rustyj

I went ahead and removed and replaced the head gasket and the valve cover gasket. The o ring for the filler tube wasnt the problem either but I went ahead and replaced it as well. I got the engine back together and went to start it....it started just fine but still leaking oil from under the rope thingamajig...like it is coming from under the fly wheel. Any suggestions? Again, there are no noise indications of anything broke internal to the motor, just the oil leak from underneath the pull rope thingy. Thanks and dont give me a hard time about my lack of small engine terminology please. This aint no 350 small block you know!!!

I think I need to replace the crank seal because the oil is not leaking out from underneath the engine but seems to be coming out from underneath the flywheel. Is there a specific flywheel puller I need to get for my engine? It is a B&S 4.5hp motor. Thanks for the help.

John--there was a problem with some engines where there was a gasket up on top of the engine block, that would start to leak, after some years of use. I just remembered that i had one of those engines, and tried, with little luck, to fix it. This came out in a bulletin, if i remember correctly!
Yes, you'll have to remove the flywheel, but, if you don't know how, better take it to a repair shop, because, if you don't do it correctly, you run the risk of breaking the nut/end of crankshaft off, and that will be FINIS!
In my case, that engine took a trip to the scrap yard!
but, do what you must do. Take it to be repaired!
Rustyj

Rusty,

Thanks for the advice. I am going to take it to a shop and have them remove the flywheel and put in the new gasket and reattach the flywheel. I am confident in my abilities to do stuff but I dont want to screw things up. Thanks again.